Digital lighting technologies, i.e. illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offer a viable alternative to traditional fluorescent, HID, and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others. Recent advances in LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications. Some of the fixtures embodying these sources feature a lighting module, including one or more LEDs capable of producing different colors, e.g. red, green, and blue, as well as a processor for independently controlling the output of the LEDs in order to generate a variety of colors and color-changing lighting effects.
In lighting systems such as those that include LED-based light sources, it is desirable to have control over one or more light sources of the lighting system. Control of one or more light sources enables specification of lighting parameters for an environment. For example, a user may directly specify one or more lighting parameters of one or more light sources. Also, for example, the user may specify the effect that is desired at one or more locations in the environment and lighting parameters of one or more light sources may be derived based on the desired effects. For example, relations between light sources of a lighting system and an environment may be present within a computer-aided design (CAD) model or a measurement model. By describing the desired effect at a location in the environment, the lighting system may derive the lighting control parameters for light sources based utilizing the CAD model to identify the light sources that have an effect at that location, to identify the distance between the light sources and the location, and to identify known variables of those light sources.
Although a CAD model or measurement model may be utilized to specify lighting effects, they may suffer from one or more drawbacks. For example, when using CAD models, any changes in the environment and/or any redirection of luminaires would have to be applied in the CAD model to provide updated lighting effects. Such updating of the CAD model may be burdensome and/or expensive. Also, for example, when using measurement models, measurement equipment would need to remain present in the environment to provide updated measurements following changes in the environment. Such measurement equipment may be expensive and/or burdensome to operate. Moreover, exiting lighting systems do not satisfactorily locate and/or track an item within an environment that is to be illuminated.
Thus, there is a need in the art to provide methods and apparatus that enable control of light output and that optionally overcome one or more drawbacks of existing lighting systems.